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At least 505 records · Page 28

Support for Astronaut's View of Mexican/ Central American Fires and on-Line Earth Observations Training Manual

A small project to compile remote sensing and in-site data to review the processes leading to the May 1998 Mexican/Central American fires was undertaken. A web page based on this project was assembled. The second project initiated involved an interactive and on-line program that will replace the paper version of the Earth Observations Preflight Training Manual. Technical support was provided to Prof. Marvin Glasser as needed.

Kaminski, Charles F., Jr.↗

A Review of Magnetic Anomaly Field Data for the Arctic Region: Geological Implications

Due to its inaccessibility and hostile physical environment remote sensing data, both airborne and satellite measurements, has been the main source of geopotential data over the entire Arctic region. Ubiquitous and significant external fields, however, hinder crustal magnetic field studies. These potential field data have been used to derive tectonic models for the two major tectonic sectors of this region, the Amerasian and Eurasian Basins. The latter is dominated by the Nansen-Gakkel or Mid-Arctic Ocean Ridge and is relatively well known. The origin and nature of the Alpha and Mendeleev Ridges, Chukchi Borderland and Canada Basin of the former are less well known and a subject of controversy. The Lomonosov Ridge divides these large provinces. In this report we will present a summary of the Arctic geopotential anomaly data derived from various sources by various groups in North America and Europe and show how these data help us unravel the last remaining major puzzle of the global plate tectonic framework. While Magnetic anomaly data represent the main focus of this study recently derived satellite gravity data (Laxon and McAdoo, 1998) are playing a major role in Arctic studies.

Taylor, Patrick T.↗

A Review of Magnetic Anomaly Field Data for the Arctic Region: Geological Implications

Due to its inaccessibility and hostile physical environment remote sensing data, both airborne and satellite measurements, has been the main source of geopotential data over the entire Arctic region. Ubiquitous and significant external fields, however, hinder crustal magnetic field studies These potential field data have been used to derive tectonic models for the two major tectonic sectors of this region, the Amerasian and Eurasian Basins. The latter is dominated by the Nansen-Gakkel or Mid-Arctic Ocean Ridge and is relatively well known. The origin and nature of the Alpha and Mendeleev Ridges, Chukchi Borderland and Canada Basin of the former are less well known and a subject of controversy. The Lomonosov Ridge divides these large provinces. In this report we will present a summary of the Arctic geopotential anomaly data derived from various sources by various groups in North America and Europe and show how these data help us unravel the last remaining major puzzle of the global plate tectonic framework. While magnetic anomaly data represent the main focus of this study recently derived satellite gravity data are playing a major role in Arctic studies.

Taylor, Patrick T.↗

A Review of the New AVIRIS Data Processing System

The processing of AVIRIS data - from the Metrum Very Large Data Store (VLDS) flight tape to delivered data products - has traditionally been performed in essentially the same way, from the beginning of the AVIRIS project up to and including the 1996 flight season. Starting with the 1997 flight season, a drastically different paradigm has been used for the processing of AVIRIS data. This change was made possible by the recent development of and related availability of affordable data storage devices.

Aronsson, Mikael↗

Evaluation and Treatment of Essential Hypertension During Short Duration Space Flight

During the last four decades of manned space flight, two individuals have successfully flown in space with the preflight diagnosis of essential hypertension (HTN). Treatment of this disease process in the astronaut population warrants special consideration particularly when selecting medication for a mission. A retrospective review of data offers two different clinical scenarios involving the treatment, or lack thereof, for essential hypertension during space flight. Case I; A Caucasian quinquagenerian diagnosed with HTN one year prior to the mission obtained flight certification after a negative diagnostic workup. The patient was placed on a diuretic. Preflight isolated blood pressure (BP) measurements averaged 138/102. Inflight, the patient electively declined medication. A 36-hour BP monitor revealed an average value of 124/87. Postflight, BP measurements returned to preflight BP values. Case II: A Caucasian quatrogenerian diagnosed with HTN 6 months prior to launch completed flight training after a negative diagnostic workup. The patient was placed on an ACE inhibiter. Preflight BP measurements averaged 130/80. Inflight, isolated BP measurements were considerably less. Normotensive values were obtained postflight. In both cases, BP values inflight were lower than pre or postflight values. Yelle et al has confirmed similar findings in the normotensive astronaut population. Spaceflight may result in fluid shifting, mild dehydration, electrolyte imbalance, orthostatic hypotension, and increased heart rates. Based on these factors, certain classes of antihypertensive agents such as vasodilators, beta-blockers, and diuretics are excluded from consideration as a primary therapeutic modality. To date, Ace Inhibitors are viewed as the more acceptable drug of choice during spaceflight. Newer classes of drugs may also provide additional choices. Presently, astronauts developing uncomplicated HTN may continue their careers when treated with the appropriate class of continue their careers when treated with the appropriate class of antihypertensive medication.

Rossum, Alfred C.↗

Comparison of X-31 Flight and Ground-Based Yawing Moment Asymmetries at High Angles of Attack

Significant yawing moment asymmetries were encountered during the high-angle-of-attack envelope expansion of the two X-31 aircraft. These asymmetries caused position saturations of the thrust-vectoring vanes and trailing-edge flaps during some stability-axis rolling maneuvers at high angles of attack. The two test aircraft had different asymmetry characteristics, and ship two has asymmetries that vary as a function of Reynolds number. Several aerodynamic modifications have been made to the X-31 forebody with the goal of minimizing the asymmetry. These modifications include adding transition strips on the forebody and noseboom, using two different length strakes, and increasing nose bluntness. Ultimately, a combination of forebody strakes, nose blunting, and noseboom transition strips reduced the yawing moment asymmetry enough to fully expand the high-angle-of-attack envelope. Analysis of the X-31 flight data is reviewed and compared to wind-tunnel and water-tunnel measurements. Several lessons learned are outlined regarding high-angle-of-attack configuration design and ground testing.

Cobleigh, Brent R.↗

Effects of Hypergravity Exposure on Plasma Oxytocin (OT) Concentrations in Pregnant and Lactating Rat Dams

From pregnancy to weaning there is a progressive elevation of plasma oxytocin (OT) levels associated with nursing activity, irrespective of litter size. In the present study, we analyzed the effects of continuous 1.5G, 1.75G and 2.0G hypergravity exposure on OT plasma concentration in prepartum (Gestation Day 20) (G20) and lactating (Postnatal day) (P10) rat dams. For this study, litter size was controlled with a yoking procedure established in our lab where individual control litters were yoked-matched to individual hypergravity litters. We reviewed all data at hypergravity irrespective of gravitational level and compared the values with the controls in both G20 (HG, n=15;SC, n=9) and P10 (HG, n=21;SC, n=16). Results showed that over time, we did observe the expected OT increase in both groups. In G20 dams, measurement of OT concentrations showed no significance. However, at P10, measurements of OT concentrations suggest a reduction of about 20% compared to established controls in our laboratory, 0.9+/-0.09 ng/ml for the controls and 0.7+/-0.06 ng/ml for centrifuged animals (p<0.02). These data suggest that exposure to centrifugation may reduce OT levels during lactation. When these plasma samples were obtained, the dams were removed from the litters, and values were not adjusted for the size of the litters. The reduction in OT with centrifugation may reflect a decrease in nursing activity or a decreased responsiveness of the mammary hypothalamic axis. In addition, we have analyzed data on plasma prolactin concentrations and mammary gland development, which may give additional insight to the results of our OT measurements.

Baer, Lisa A.↗

Comparison of X-31 Flight and Ground-Based Yawing Moment Asymmetries at High Angles of Attack

Significant yawing moment asymmetries were encountered during the high-angle-of-attack envelope expansion of the two X-31 aircraft. These asymmetries caused position saturations of the thrust-vectoring vanes and trailing-edge flaps during some stability-axis rolling maneuvers at high angles of attack. The two test aircraft had different asymmetry characteristics, and ship 2 has asymmetries that vary as a function of Reynolds number. Several aerodynamic modifications have been made to the X-31 forebody with the goal of minimizing the asymmetry. These modifications include adding transition strips on the forebody and noseboom, using two different length strakes, and increasing nose bluntness. Ultimately, a combination of forebody strakes, nose blunting, and noseboom transition strips reduced the yawing moment asymmetry enough to fully expand the high-angle-of-attack envelope. Analysis of the X-31 flight data is reviewed and compared to wind-tunnel and water-tunnel measurements. Several lessons learned are outlined regarding high-angle-of-attack configuration design and ground testing.

Cobleigh, Brent↗

Recent measurements for hadrontherapy and space radiation: nuclear physics

The particles and energies commonly used for hadron therapy overlap the low end of the charge and energy range of greatest interest for space radiation applications, Z=1-26 and approximately 100-1000 MeV/nucleon. It has been known for some time that the nuclear interactions of the incident ions must be taken into account both in treatment planning and in understanding and addressing the effects of galactic cosmic ray ions on humans in space. Until relatively recently, most of the studies of nuclear fragmentation and transport in matter were driven by the interests of the nuclear physics and later, the hadron therapy communities. However, the experimental and theoretical methods and the accelerator facilities developed for use in heavy ion nuclear physics are directly applicable to radiotherapy and space radiation studies. I will briefly review relevant data taken recently at various accelerators, and discuss the implications of the measurements for radiotherapy, radiobiology and space radiation research.

NASA Discipline Radiation Health↗

Isotopic Constraints on the Petrology of Martian Meteorites

The SNC (martian) meteorites exhibit complex isotopic characteristics that yield information both about the ages of individual meteorites as well as information about the petrogenetic processes that produced both individual samples and about the origins of suites and sub-suites within the SNC clan. Here I review these data, reiterate earlier interpretations, and offer some new conclusions.

Jones, J. H.↗

Introduction to Flight Test Engineering [Introduction Aux Techniques Des Essais En Vol]

Flight test is at the core of what organizations must do in order to validate the operation and systems on an aircraft. While the AGARDograph series 300 and 160 series deal with aspects of this testing, this volume pulls it all together as an introduction to the process required to do effective flight test engineering. This volume was originally published in 1995. Its utility has been proven in that many flight test organizations and universities have requested copies for their engineers and students. It was felt that re-issuing it in a new format designed for electronic publication would be valuable to the community. This second printing changes none of the text, but rather reformats it. All the original references to AGARD (instead of RTO) are left in place so that none of the flavor of the original publication is lost. This is the Introductory Volume to the Flight Test Techniques Series. It is a general introduction to the various activities and aspects of Flight Test Engineering that must be considered when planning, conducting, and reporting a flight test program. Its main intent is to provide a broad overview to the novice engineer or to other people who have a need to interface with specialists within the flight test community. The first two Sections provide some insight into the question of why flight test and give a short history of flight test engineering. Sections 3 through 10 deal with the preparation for flight testing. They provide guidance on the preliminary factors that must be considered; the composition of the test team; the logistic support requirements; the instrumentation and data processing requirements; the flight test plan; the associated preliminary ground tests; and last, but by no means least, discuss safety aspects. Sections 11 through 27 describe the various types of flight tests that are usually conducted during the development and certification of a new or modified aircraft type. Each Section offers a brief introduction to the topic under consideration, and the nature and the objectives of the tests to be conducted. It lists the test instrumentation (and, where appropriate, other test equipment and facilities) required, describes the test maneuvers to be executed, and indicates the way in which the test data is selected, analyzed, and presented. The various activities that should take place between test flights are presented next. Items that are covered are: who to debrief; what type of reports to send where: types of data analysis required for next flight; review of test data to make a comparison to predicted data and some courses of action if there is not good agreement; and comments on selecting the next test flight. The activities that must take place upon completion of the test program are presented. The types of reports and briefings that should take place and a discussion of some of the uses of the flight test data are covered. A brief forecast is presented of where present trends may be leading.

Test facilities↗

Behavioral health in Antarctica: implications for long-duration space missions

Ideally, evidence from long-duration spaceflight should be used to predict likely occurrences of behavioral health events and for planning management strategies for such events. With small numbers of space travelers, and limited long-duration missions of a year or more, Earth analogues and simulations must be used as the evidence base, despite such analogues lacking microgravity, radiation, rapidly altering photoperiodicity, and fidelity to space. Antarctic health data are reviewed and an assessment made of the likely frequency of behavioral health events. Based on the Antarctic evidence, the likelihood of behavioral health problems in space is low. However, such cases may be serious and of high consequence, placing considerable demands on the mission crew and ground support to achieve a successful outcome, given the availability of pharmaceuticals and resources.

Review↗

Diagnostic Imaging in the Medical Support of the Future Missions to the Moon

This viewgraph presentation is a course that reviews the diagnostic imaging techniques available for medical support on the future moon missions. The educational objectives of the course are to: 1) Update the audience on the curreultrasound imaging in space flight; 2) Discuss the unique aspects of conducting ultrasound imaging on ISS, interplanetary transit, ultrasound imaging on ISS, interplanetary transit, and lunar surface operations; and 3) Review preliminary data obtained in simulations of medical imaging in lunar surface operations.

Sargsyan, Ashot E.↗

Large Scale Magnetostrictive Valve Actuator

Marshall Space Flight Center's Valves, Actuators and Ducts Design and Development Branch developed a large scale magnetostrictive valve actuator. The potential advantages of this technology are faster, more efficient valve actuators that consume less power and provide precise position control and deliver higher flow rates than conventional solenoid valves. Magnetostrictive materials change dimensions when a magnetic field is applied; this property is referred to as magnetostriction. Magnetostriction is caused by the alignment of the magnetic domains in the material s crystalline structure and the applied magnetic field lines. Typically, the material changes shape by elongating in the axial direction and constricting in the radial direction, resulting in no net change in volume. All hardware and testing is complete. This paper will discuss: the potential applications of the technology; overview of the as built actuator design; discuss problems that were uncovered during the development testing; review test data and evaluate weaknesses of the design; and discuss areas for improvement for future work. This actuator holds promises of a low power, high load, proportionally controlled actuator for valves requiring 440 to 1500 newtons load.

Richard, James A.↗

The Disk-Jet Connection in Radio-Loud AGN: The X-Ray Perspective

Unification schemes assume that radio-loud active galactic nuclei (AGN) contain an accretion disk and a relativistic jet perpendicular to the disk, and an obscuring molecular torus. The jet dominance decreases with larger viewing angles from blazars to Broad-Line and Narrow-Line Radio Galaxies. A fundamental question is how accretion and ejecta are related. The X-rays provide a convenient window to study these issues, as they originate in the innermost nuclear regions and penetrate large obscuring columns. I review the data, using observations by Chandra but also from other currently operating high-energy experiments. Synergy with the upcoming GLAST mission will also be highlighted.

Sambruna, Rita↗

Rashes and Exanthems on Long Duration Space Flights

INTRODUCTION: As NASA expands its human space exploration to the Moon, Mars and beyond, it will be presented with many challenges, not the least of which will be dealing with medical conditions, which on earth are simple, but take on new levels of complexity in space habitats. Skin conditions exemplify this complexity. METHODS AND RESULTS: While skin conditions account for 7 % of outpatient presentations to a primary care provider in the United States, NASA Longitudinal Study of Astronaut Health (LSAH) database indicates that cutaneous manifestations are significantly prevalent on-orbit. Reviewing this data for US astronauts, there have been 90 total cases of skin rashes during 27.34 person-years of spaceflight, or 3.29 cases/person. Specifically, STS-1 though 114 had 56 cases, ISS Expeditions 1 though 13 had 7 cases, Mir had 4 cases, Skylab had 5 cases and the Apollo program had 18 cases. If there was a period of 24 hours or more between rashes in the same crewmember, this was counted as an additional case. DISCUSSION: This prevalence is likely due, in some part, to constraints of hygiene and to immunologic changes that occur. The stresses of microgravity and austere Earth environments such as the Antarctic, submarine and military deployments, no doubt, similarly contribute to cutaneous reactions; but the difference of the environments are significant enough to warrant further study and discussion. This paper will discuss rashes, exanthems, and cutaneous reactions in space habitats; it will address diagnosis, causation, mitigation and treatment of skin conditions seen on orbit, to date, with a look to anticipating what may be seen with larger crews on future extended duration expeditions.

Ilscus, L.S.↗